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SUPREME COURT OF THE UNITED STATES

Nos. 91-543, 91-558 and 91-563

NEW YORK, PETITIONER

91-543 v. UNITED STATES et al.

COUNTY OF ALLEGANY, NEW YORK, PETITIONER

91-558v.

UNITED STATES

COUNTY OF CORTLAND, NEW YORK, PETITIONER

91-563v.

UNITED STATES et al.

on writs of certiorari to the united states court of
appeals for the second circuit

[June 19, 1992]

Justice O'Connor delivered the opinion of the Court.

We live in a world full of low level radioactive waste.
Radioactive material is present in luminous watch dials,
smoke alarms, measurement devices, medical fluids,
research materials, and the protective gear and construction
materials used by workers at nuclear power plants. Low
level radioactive waste is generated by the Government, by
hospitals, by research institutions, and by various industries. The waste must be isolated from humans for long
periods of time, often for hundreds of years. Millions of
cubic feet of low level radioactive waste must be disposed of
each year. See App. 110a 111a; Berkovitz, Waste Wars: Did
Congress "Nuke" State Sovereignty in the Low Level
Radioactive Waste Policy Amendments Act of 1985?, 11
Harv. Envtl. L. Rev. 437, 439-440 (1987).

Our Nation's first site for the land disposal of commercial
low level radioactive waste opened in 1962 in Beatty,
Nevada. Five more sites opened in the following decade:
Maxey Flats, Kentucky (1963), West Valley, New York
(1963), Hanford, Washington (1965), Sheffield, Illinois
(1967), and Barnwell, South Carolina (1971). Between 1975
and 1978, the Illinois site closed because it was full, and
water management problems caused the closure of the sites
in Kentucky and New York. As a result, since 1979 only
three disposal sites--those in Nevada, Washington, and
South Carolina--have been in operation. Waste generated
in the rest of the country must be shipped to one of these
three sites for disposal. See Low Level Radioactive Waste
Regulation 39-40 (M. Burns ed. 1988).

In 1979, both the Washington and Nevada sites were
forced to shut down temporarily, leaving South Carolina to
shoulder the responsibility of storing low level radioactive
waste produced in every part of the country. The Governorof South Carolina, understandably perturbed, ordered a
50% reduction in the quantity of waste accepted at the
Barnwell site. The Governors of Washington and Nevada
announced plans to shut their sites permanently. App.
142a, 152a.

Faced with the possibility that the Nation would be left
with no disposal sites for low level radioactive waste,
Congress responded by enacting the Low Level Radioactive
Waste Policy Act, Pub. L. 96-573, 94 Stat. 3347. Relying
largely on a report submitted by the National Governors'
Association, see App. 105a 141a, Congress declared a
federal policy of holding each State "responsible for providing for the availability of capacity either within or outside
the State for the disposal of low level radioactive waste
generated within its borders," and found that such waste
could be disposed of "most safely and efficiently . . . on a
regional basis." § 4(a)(1), 94 Stat. 3348. The 1980 Act
authorized States to enter into regional compacts that, once
ratified by Congress, would have the authority beginning in
1986 to restrict the use of their disposal facilities to waste
generated within member States. § 4(a)(2)(B), 94 Stat.
3348. The 1980 Act included no penalties for States that
failed to participate in this plan.

By 1985, only three approved regional compacts had
operational disposal facilities; not surprisingly, these were
the the compacts formed around South Carolina, Nevada,
and Washington, the three sited States. The following year,
the 1980 Act would have given these three compacts the
ability to exclude waste from nonmembers, and the remaining 31 States would have had no assured outlet for their
low level radioactive waste. With this prospect looming,
Congress once again took up the issue of waste disposal.
The result was the legislation challenged here, the Low Level Radioactive Waste Policy Amendments Act of 1985.

The 1985 Act was again based largely on a proposal
submitted by the National Governors' Association. In broad
outline, the Act embodies a compromise among the sitedand unsited States. The sited States agreed to extend for
seven years the period in which they would accept low level
radioactive waste from other States. In exchange, the
unsited States agreed to end their reliance on the sited
States by 1992.

The mechanics of this compromise are intricate. The Act
directs: "Each State shall be responsible for providing,
either by itself or in cooperation with other States, for the
disposal of . . . low level radioactive waste generated within
the State," 42 U.S.C. § 2021c(a)(1)(A), with the exception
of certain waste generated by the Federal Government,
§§ 2021c(a)(1)(B), 2021c(b). The Act authorizes States to "enter into such [interstate] compacts as may be necessary
to provide for the establishment and operation of regional
disposal facilities for low level radioactive waste." § 2021d(a)(2). For an additional seven years beyond the period
contemplated by the 1980 Act, from the beginning of 1986
through the end of 1992, the three existing disposal sites "shall make disposal capacity available for low level
radioactive waste generated by any source," with certain
exceptions not relevant here. § 2021e(a)(2). But the three
States in which the disposal sites are located are permitted
to exact a graduated surcharge for waste arriving from
outside the regional compact--in 1986-1987, $10 per cubic
foot; in 1988-1989, $20 per cubic foot; and in 1990-1992,
$40 per cubic foot. § 2021e(d)(1). After the seven year
transition period expires, approved regional compacts may
exclude radioactive waste generated outside the region.
§ 2021d(c).

The Act provides three types of incentives to encourage
the States to comply with their statutory obligation to
provide for the disposal of waste generated within their
borders.

1. Monetary incentives. One quarter of the surcharges
collected by the sited States must be transferred to an
escrow account held by the Secretary of Energy. § 2021e(d)(2)(A). The Secretary then makes payments from thisaccount to each State that has complied with a series of
deadlines. By July 1, 1986, each State was to have ratified
legislation either joining a regional compact or indicating an
intent to develop a disposal facility within the State.
§§ 2021e(e)(1)(A), 2021e(d)(2)(B)(i). By January 1, 1988,
each unsited compact was to have identified the State in
which its facility would be located, and each compact or
stand alone State was to have developed a siting plan and
taken other identified steps. §§ 2021e(e)(1)(B), 2021e(d)(2)(B)(ii). By January 1, 1990, each State or compact was to
have filed a complete application for a license to operate a
disposal facility, or the Governor of any State that had not
filed an application was to have certified that the State
would be capable of disposing of all waste generated in the
State after 1992. §§ 2021e(e)(1)(C), 2021e(d)(2)(B)(iii). The
rest of the account is to be paid out to those States or
compacts able to dispose of all low level radioactive waste
generated within their borders by January 1, 1993.
§ 2021e(d)(2)(B)(iv). Each State that has not met the 1993
deadline must either take title to the waste generated
within its borders or forfeit to the waste generators the
incentive payments it has received. § 2021e(d)(2)(C).

2. Access incentives. The second type of incentive
involves the denial of access to disposal sites. States that
fail to meet the July 1986 deadline may be charged twice
the ordinary surcharge for the remainder of 1986 and
may be denied access to disposal facilities thereafter.
§ 2021e(e)(2)(A). States that fail to meet the 1988 deadline
may be charged double surcharges for the first half of 1988
and quadruple surcharges for the second half of 1988, and
may be denied access thereafter. § 2021e(e)(2)(B). States
that fail to meet the 1990 deadline may be denied access.
§ 2021e(e)(2)(C). Finally, States that have not filed complete applications by January 1, 1992, for a license to
operate a disposal facility, or States belonging to compacts
that have not filed such applications, may be charged triple
surcharges. §§ 2021e(e)(1)(D), 2021e(e)(2)(D).

3. The take title provision. The third type of incentive is
the most severe. The Act provides:

"If a State (or, where applicable, a compact region) in
which low level radioactive waste is generated is
unable to provide for the disposal of all such waste
generated within such State or compact region by
January 1, 1996, each State in which such waste is
generated, upon the request of the generator or owner
of the waste, shall take title to the waste, be obligated
to take possession of the waste, and shall be liable for
all damages directly or indirectly incurred by such
generator or owner as a consequence of the failure of
the State to take possession of the waste as soon after
January 1, 1996, as the generator or owner notifies the
State that the waste is available for shipment."
§ 2021e(d)(2)(C).

These three incentives are the focus of petitioners' constitutional challenge.

In the seven years since the Act took effect, Congress has
approved nine regional compacts, encompassing 42 of the
States. All six unsited compacts and four of the unaffiliated
States have met the first three statutory milestones. Brief
for United States 10, n. 19; id., at 13, n. 25.

New York, a State whose residents generate a relatively
large share of the Nation's low level radioactive waste, did
not join a regional compact. Instead, the State complied
with the Act's requirements by enacting legislation providing for the siting and financing of a disposal facility in New
York. The State has identified five potential sites, three in
Allegany County and two in Cortland County. Residents of
the two counties oppose the State's choice of location. App.
29a-30a, 66a 68a.

Petitioners--the State of New York and the two counties--filed this suit against the United States in 1990.
They sought a declaratory judgment that the Act is inconsistent with the Tenth and Eleventh Amendments to theConstitution, with the Due Process Clause of the Fifth
Amendment, and with the Guarantee Clause of Article IV
of the Constitution. The States of Washington, Nevada,
and South Carolina intervened as defendants. The District
Court dismissed the complaint. 757 F. Supp. 10 (NDNY
1990). The Court of Appeals affirmed. 942 F. 2d 114 (CA2
1991). Petitioners have abandoned their Due Process and
Eleventh Amendment claims on their way up the appellate
ladder; as the case stands before us, petitioners claim only
that the Act is inconsistent with the Tenth Amendment and
the Guarantee Clause.

In 1788, in the course of explaining to the citizens of New
York why the recently drafted Constitution provided for
federal courts, Alexander Hamilton observed: "The erection
of a new government, whatever care or wisdom may
distinguish the work, cannot fail to originate questions of
intricacy and nicety; and these may, in a particular manner,
be expected to flow from the the establishment of a constitution founded upon the total or partial incorporation of a
number of distinct sovereignties." The Federalist No. 82, p.
491 (C. Rossiter ed. 1961). Hamilton's prediction has
proved quite accurate. While no one disputes the proposition that "[t]he Constitution created a Federal Government
of limited powers," Gregory v. Ashcroft, 501 U. S. ___, ___
(1991) (slip op., at 3); and while the Tenth Amendment
makes explicit that "[t]he powers not delegated to the
United States by the Constitution, nor prohibited by it to
the States, are reserved to the States respectively, or to the
people"; the task of ascertaining the constitutional line
between federal and state power has given rise to many of
the Court's most difficult and celebrated cases. At least as
far back as Martin v. Hunter's Lessee, 1 Wheat. 304, 324
(1816), the Court has resolved questions "of great importance and delicacy" in determining whether particular
sovereign powers have been granted by the Constitution to
the Federal Government or have been retained by the
States.

These questions can be viewed in either of two ways. In
some cases the Court has inquired whether an Act of
Congress is authorized by one of the powers delegated to
Congress in Article I of the Constitution. See, e. g., Perez v.
United States, 402 U.S. 146 (1971); McCulloch v. Maryland, 4 Wheat. 316 (1819). In other cases the Court has
sought to determine whether an Act of Congress invades
the province of state sovereignty reserved by the Tenth
Amendment. See, e. g., Garcia v. San Antonio Metropolitan
Transit Authority, 469 U.S. 528 (1985); Lane County v.
Oregon, 7 Wall. 71 (1869). In a case like this one, involving
the division of authority between federal and state governments, the two inquiries are mirror images of each other.
If a power is delegated to Congress in the Constitution, the
Tenth Amendment expressly disclaims any reservation of
that power to the States; if a power is an attribute of state
sovereignty reserved by the Tenth Amendment, it is
necessarily a power the Constitution has not conferred on
Congress. See United States v. Oregon, 366 U.S. 643, 649
(1961); Case v. Bowles, 327 U.S. 92, 102 (1946); Oklahoma
ex rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 534
(1941).

It is in this sense that the Tenth Amendment "states but
a truism that all is retained which has not been surrendered." United States v. Darby, 312 U.S. 100, 124 (1941).
As Justice Story put it, "[t]his amendment is a mere
affirmation of what, upon any just reasoning, is a necessary
rule of interpreting the constitution. Being an instrument
of limited and enumerated powers, it follows irresistibly,
that what is not conferred, is withheld, and belongs to the
state authorities." 3 J. Story, Commentaries on the
Constitution of the United States 752 (1833). This has been
the Court's consistent understanding: "The States unquestionably do retai[n] a significant measure of sovereign
authority . . . to the extent that the Constitution has not
divested them of their original powers and transferred those
powers to the Federal Government." Garcia v. San Antonio
Metropolitan Transit Authority, supra, at 549 (internal
quotation marks omitted).

Congress exercises its conferred powers subject to the
limitations contained in the Constitution. Thus, for
example, under the Commerce Clause Congress may regulate publishers engaged in interstate commerce, but
Congress is constrained in the exercise of that power bythe First Amendment. The Tenth Amendment likewise
restrains the power of Congress, but this limit is not
derived from the text of the Tenth Amendment itself,
which, as we have discussed, is essentially a tautology.
Instead, the Tenth Amendment confirms that the power of
the Federal Government is subject to limits that may, in a
given instance, reserve power to the States. The Tenth
Amendment thus directs us to determine, as in this case,
whether an incident of state sovereignty is protected by a
limitation on an Article I power.

The benefits of this federal structure have been extensively catalogued elsewhere, see, e. g., Gregory v. Ashcroft,
supra, at ___%___; Merritt, The Guarantee Clause and State
Autonomy: Federalism for a Third Century, 88 Colum. L.
Rev. 1, 3-10 (1988); McConnell, Federalism: Evaluating the
Founders' Design, 54 U. Chi. L. Rev. 1484, 1491-1511
(1987), but they need not concern us here. Our task would
be the same even if one could prove that federalism secured
no advantages to anyone. It consists not of devising our
preferred system of government, but of understanding and
applying the framework set forth in the Constitution. "The
question is not what power the Federal Government ought
to have but what powers in fact have been given by the
people." United States v. Butler, 297 U.S. 1, 63 (1936).

This framework has been sufficiently flexible over the
past two centuries to allow for enormous changes in thenature of government. The Federal Government undertakes activities today that would have been unimaginable
to the Framers in two senses; first, because the Framers
would not have conceived that any government would
conduct such activities; and second, because the Framers
would not have believed that the Federal Government,
rather than the States, would assume such responsibilities.
Yet the powers conferred upon the Federal Government by
the Constitution were phrased in language broad enough to
allow for the expansion of the Federal Government's role.
Among the provisions of the Constitution that have been
particularly important in this regard, three concern us here.

First, the Constitution allocates to Congress the power "[t]o regulate Commerce . . . among the several States."
Art. I, § 8, cl. 3. Interstate commerce was an established
feature of life in the late 18th century. See, e. g., The
Federalist No. 42, p. 267 (C. Rossiter ed. 1961) ("The defect
of power in the existing Confederacy to regulate the
commerce between its several members [has] been clearly
pointed out by experience"). The volume of interstate
commerce and the range of commonly accepted objects of
government regulation have, however, expanded considerably in the last 200 years, and the regulatory authority of
Congress has expanded along with them. As interstate
commerce has become ubiquitous, activities once considered
purely local have come to have effects on the national
economy, and have accordingly come within the scope of
Congress' commerce power. See, e. g., Katzenbach v.
McClung, 379 U.S. 294 (1964); Wickard v. Filburn, 317 U.S. 111 (1942).

Second, the Constitution authorizes Congress "to pay the
Debts and provide for the . . . general Welfare of the United
States." Art. I, § 8, cl. 1. As conventional notions of the
proper objects of government spending have changed over
the years, so has the ability of Congress to "fix the terms on
which it shall disburse federal money to the States."
Pennhurst State School and Hospital v. Halderman, 451 U.S. 1, 17 (1981). Compare, e. g., United States v. Butler,
supra, at 72-75 (spending power does not authorize
Congress to subsidize farmers), with South Dakota v. Dole,
483 U.S. 203 (1987) (spending power permits Congress to
condition highway funds on States' adoption of minimum
drinking age). While the spending power is "subject to
several general restrictions articulated in our cases," id., at
207, these restrictions have not been so severe as to prevent
the regulatory authority of Congress from generally keeping
up with the growth of the federal budget.

The Court's broad construction of Congress' power under
the Commerce and Spending Clauses has of course been
guided, as it has with respect to Congress' power generally,
by the Constitution's Necessary and Proper Clause, which
authorizes Congress "[t]o make all Laws which shall be
necessary and proper for carrying into Execution the
foregoing Powers." U. S. Const., Art. I., § 8, cl. 18. See,
e. g., Legal Tender Case (Juilliard v. Greenman), 110 U.S. 421, 449-450 (1884); McCulloch v. Maryland, 4 Wheat., at
411-421.

Finally, the Constitution provides that "the Laws of the
United States . . . shall be the supreme Law of the Land . . .
any Thing in the Constitution or Laws of any State to the
Contrary notwithstanding." U. S. Const., Art. VI, cl. 2. As
the Federal Government's willingness to exercise power
within the confines of the Constitution has grown, the
authority of the States has correspondingly diminished to
the extent that federal and state policies have conflicted.
See, e. g., Shaw v. Delta Air Lines, Inc., 463 U.S. 85 (1983).
We have observed that the Supremacy Clause gives the
Federal Government "a decided advantage in th[e] delicate
balance" the Constitution strikes between State and
Federal power. Gregory v. Ashcroft, 501 U. S., at ___ (slip
op., at 6).

The actual scope of the Federal Government's authority
with respect to the States has changed over the years,
therefore, but the constitutional structure underlying andlimiting that authority has not. In the end, just as a cup
may be half empty or half full, it makes no difference
whether one views the question at issue in this case as one
of ascertaining the limits of the power delegated to the
Federal Government under the affirmative provisions of the
Constitution or one of discerning the core of sovereignty
retained by the States under the Tenth Amendment.
Either way, we must determine whether any of the three
challenged provisions of the Low Level Radioactive Waste
Policy Amendments Act of 1985 oversteps the boundary
between federal and state authority.

Petitioners do not contend that Congress lacks the power
to regulate the disposal of low level radioactive waste.
Space in radioactive waste disposal sites is frequently sold
by residents of one State to residents of another. Regulation of the resulting interstate market in waste disposal is
therefore well within Congress' authority under the
Commerce Clause. Cf. Philadelphia v. New Jersey, 437 U.S. 617, 621-623 (1978); Fort Gratiot Sanitary Landfill,
Inc. v. Michigan Dept. of Natural Resources, 504 U. S. ___,
___ (1992) (slip op., at 5). Petitioners likewise do not
dispute that under the Supremacy Clause Congress could,
if it wished, pre-empt state radioactive waste regulation.
Petitioners contend only that the Tenth Amendment limits
the power of Congress to regulate in the way it has chosen.
Rather than addressing the problem of waste disposal by
directly regulating the generators and disposers of waste,
petitioners argue, Congress has impermissibly directed the
States to regulate in this field.

Most of our recent cases interpreting the Tenth Amendment have concerned the authority of Congress to subject
state governments to generally applicable laws. The
Court's jurisprudence in this area has traveled an unsteady
path. See Maryland v. Wirtz, 392 U.S. 183 (1968) (state
schools and hospitals are subject to Fair Labor StandardsAct); National League of Cities v. Usery, 426 U.S. 833
(1976) (overruling Wirtz) (state employers are not subject to
Fair Labor Standards Act); Garcia v. San Antonio Metropolitan Transit Authority, 469 U.S. 528 (1985) (overruling
National League of Cities) (state employers are once again
subject to Fair Labor Standards Act). See also New York v.
United States, 326 U.S. 572 (1946); Fry v. United States,
421 U.S. 542 (1975); Transportation Union v. Long Island
R. Co., 455 U.S. 678 (1982); EEOC v. Wyoming, 460 U.S. 226 (1983); South Carolina v. Baker, 485 U.S. 505 (1988);
Gregory v. Ashcroft, 501 U. S. ___ (1991). This case presents no occasion to apply or revisit the holdings of any of
these cases, as this is not a case in which Congress has
subjected a State to the same legislation applicable to
private parties. Cf. FERC v. Mississippi, 456 U.S. 742,
758-759 (1982).

This case instead concerns the circumstances under which
Congress may use the States as implements of regulation;
that is, whether Congress may direct or otherwise motivate
the States to regulate in a particular field or a particular
way. Our cases have established a few principles that
guide our resolution of the issue.

As an initial matter, Congress may not simply "commandee[r] the legislative processes of the States by directly
compelling them to enact and enforce a federal regulatory
program." Hodel v. Virginia Surface Mining & Reclamation
Assn., Inc., 452 U.S. 264, 288 (1981). In Hodel, the Court
upheld the Surface Mining Control and Reclamation Act of
1977 precisely because it did not "commandeer" the States
into regulating mining. The Court found that "the States
are not compelled to enforce the steep slope standards, to
expend any state funds, or to participate in the federal
regulatory program in any manner whatsoever. If a State
does not wish to submit a proposed permanent program
that complies with the Act and implementing regulations,the full regulatory burden will be borne by the Federal
Government." Ibid.

The Court reached the same conclusion the following year
in FERC v. Mississippi, supra. At issue in FERC was the
Public Utility Regulatory Policies Act of 1978, a federal
statute encouraging the States in various ways to develop
programs to combat the Nation's energy crisis. We observed that "this Court never has sanctioned explicitly a
federal command to the States to promulgate and enforce
laws and regulations." Id., at 761-762. As in Hodel, the
Court upheld the statute at issue because it did not view
the statute as such a command. The Court emphasized: "Titles I and III of [the Public Utility Regulatory Policies
Act of 1978 (PURPA)] require only consideration of federal
standards. And if a State has no utilities commission, or
simply stops regulating in the field, it need not even
entertain the federal proposals." 456 U. S., at 764 (emphasis in original). Because "[t]here [wa]s nothing in PURPA
`directly compelling' the States to enact a legislative
program," the statute was not inconsistent with the
Constitution's division of authority between the Federal
Government and the States. Id., at 765 (quoting Hodel v.
Virginia Surface Mining & Reclamation Assn., Inc., supra,
at 288). See also South Carolina v. Baker, supra, at 513
(noting "the possibility that the Tenth Amendment might
set some limits on Congress' power to compel States to
regulate on behalf of federal interests"); Garcia v. San
Antonio Metropolitan Transit Authority, supra, at 556
(same).

These statements in FERC and Hodel were not innovations. While Congress has substantial powers to govern the
Nation directly, including in areas of intimate concern to
the States, the Constitution has never been understood to
confer upon Congress the ability to require the States to
govern according to Congress' instructions. See Coyle v.
Oklahoma, 221 U.S. 559, 565 (1911). The Court has been
explicit about this distinction. "Both the States and theUnited States existed before the Constitution. The people,
through that instrument, established a more perfect union
by substituting a national government, acting, with ample
power, directly upon the citizens, instead of the Confederate
government, which acted with powers, greatly restricted,
only upon the States." Lane County v. Oregon, 7 Wall., at
76 (emphasis added). The Court has made the same point
with more rhetorical flourish, although perhaps with less
precision, on a number of occasions. In Chief Justice
Chase's much quoted words, "the preservation of the States,
and the maintenance of their governments, are as much
within the design and care of the Constitution as the
preservation of the Union and the maintenance of the
National government. The Constitution, in all its provisions, looks to an indestructible Union, composed of
indestructible States." Texas v. White, 7 Wall. 700, 725
(1869). See also Metcalf & Eddy v. Mitchell, 269 U.S. 514,
523 (1926) ("neither government may destroy the other nor
curtail in any substantial manner the exercise of its
powers"); Tafflin v. Levitt, 493 U.S. 455, 458 (1990) ("under
our federal system, the States possess sovereignty concurrent with that of the Federal Government"); Gregory v.
Ashcroft, 501 U. S., at ___ (slip op., at 7) ("the States retain
substantial sovereign powers under our constitutional
scheme, powers with which Congress does not readily
interfere").

Indeed, the question whether the Constitution should
permit Congress to employ state governments as regulatory
agencies was a topic of lively debate among the Framers.
Under the Articles of Confederation, Congress lacked the
authority in most respects to govern the people directly. In
practice, Congress "could not directly tax or legislate upon
individuals; it had no explicit `legislative' or `governmental'
power to make binding `law' enforceable as such." Amar, Of
Sovereignty and Federalism, 96 Yale L. J. 1425, 1447
(1987).

The inadequacy of this governmental structure was
responsible in part for the Constitutional Convention.
Alexander Hamilton observed: "The great and radical vice
in the construction of the existing Confederation is in the
principle of legislation for states or governments, in
their corporate or collective capacities, and as contradistinguished from the individuals of whom they consist."
The Federalist No. 15, p. 108 (C. Rossiter ed. 1961). As
Hamilton saw it, "we must resolve to incorporate into our
plan those ingredients which may be considered as forming
the characteristic difference between a league and a
government; we must extend the authority of the Union to
the persons of the citizens--the only proper objects of
government." Id., at 109. The new National Government "must carry its agency to the persons of the citizens. It
must stand in need of no intermediate legislations . . . .
The government of the Union, like that of each State, must
be able to address itself immediately to the hopes and fears
of individuals." Id., No. 16, p. 116.

The Convention generated a great number of proposals
for the structure of the new Government, but two quickly
took center stage. Under the Virginia Plan, as first
introduced by Edmund Randolph, Congress would exercise
legislative authority directly upon individuals, without
employing the States as intermediaries. 1 Records of the
Federal Convention of 1787, p. 21 (M. Farrand ed. 1911).
Under the New Jersey Plan, as first introduced by William
Paterson, Congress would continue to require the approval
of the States before legislating, as it has under the Articles
of Confederation. 1 id., 243-244. These two plans underwent various revisions as the Convention progressed, but
they remained the two primary options discussed by the
delegates. One frequently expressed objection to the New
Jersey Plan was that it might require the Federal Government to coerce the States into implementing legislation. As
Randolph explained the distinction, "[t]he true question is
whether we shall adhere to the federal plan [i.e., the NewJersey Plan], or introduce the national plan. The insufficiency of the former has been fully displayed . . . . There
are but two modes, by which the end of a Gen[eral] Gov[ernment] can be attained: the 1st is by coercion as proposed by Mr. P[aterson's] plan[, the 2nd] by real legislation
as prop[osed] by the other plan. Coercion [is] impracticable,
expensive, cruel to individuals. . . . We must resort therefore
to a national Legislation over individuals." 1 id., at
255-256 (emphasis in original). Madison echoed this view: "The practicability of making laws, with coercive sanctions,
for the States as political bodies, had been exploded on all
hands." 2 id., at 9.

Under one preliminary draft of what would become the
New Jersey Plan, state governments would occupy a
position relative to Congress similar to that contemplated
by the Act at issue in this case: "[T]he laws of the United
States ought, as far as may be consistent with the common
interests of the Union, to be carried into execution by the
judiciary and executive officers of the respective states,
wherein the execution thereof is required." 3 id., at 616.
This idea apparently never even progressed so far as to be
debated by the delegates, as contemporary accounts of the
Convention do not mention any such discussion. The
delegates' many descriptions of the Virginia and New
Jersey Plans speak only in general terms about whether
Congress was to derive its authority from the people or
from the States, and whether it was to issue directives to
individuals or to States. See 1 id., at 260-280.

In the end, the Convention opted for a Constitution in
which Congress would exercise its legislative authority
directly over individuals rather than over States; for a
variety of reasons, it rejected the New Jersey Plan in favor
of the Virgina Plan. 1 id., at 313. This choice was made
clear to the subsequent state ratifying conventions. Oliver
Ellsworth, a member of the Connecticut delegation in
Philadelphia, explained the distinction to his State's
convention: "This Constitution does not attempt to coercesovereign bodies, states, in their political capacity. . . . But
this legal coercion singles out the . . . individual." 2 J.
Elliot, Debates on the Federal Constitution 197 (2d ed.
1863). Charles Pinckney, another delegate at the Constitutional Convention, emphasized to the South Carolina House
of Representatives that in Philadelphia "the necessity of
having a government which should at once operate upon the
people, and not upon the states, was conceived to be
indispensable by every delegation present." 4 id., at 256.
Rufus King, one of Massachusetts' delegates, returned home
to support ratification by recalling the Commonwealth's
unhappy experience under the Articles of Confederation and
arguing: "Laws, to be effective, therefore, must not be laid
on states, but upon individuals." 2 id., at 56. At New
York's convention, Hamilton (another delegate in Philadelphia) exclaimed: "But can we believe that one state will
ever suffer itself to be used as an instrument of coercion?
The thing is a dream; it is impossible. Then we are brought
to this dilemma--either a federal standing army is to
enforce the requisitions, or the federal treasury is left
without supplies, and the government without support.
What, sir, is the cure for this great evil? Nothing, but to
enable the national laws to operate on individuals, in the
same manner as those of the states do." 2 id., at 233. At
North Carolina's convention, Samuel Spencer recognized
that "all the laws of the Confederation were binding on the
states in their political capacities, . . . but now the thing is
entirely different. The laws of Congress will be binding on
individuals." 4 id., at 153.

In providing for a stronger central government, therefore,
the Framers explicitly chose a Constitution that confers
upon Congress the power to regulate individuals, not
States. As we have seen, the Court has consistently
respected this choice. We have always understood that
even where Congress has the authority under the Constitution to pass laws requiring or prohibiting certain acts, it
lacks the power directly to compel the States to require orprohibit those acts. E. g., FERC v. Mississippi, 456 U. S.,
at 762-766; Hodel v. Virginia Surface Mining & Reclamation Assn., Inc., 452 U. S., at 288-289; Lane County v.
Oregon, 7 Wall., at 76. The allocation of power contained
in the Commerce Clause, for example, authorizes Congress
to regulate interstate commerce directly; it does not
authorize Congress to regulate state governments' regulation of interstate commerce.

This is not to say that Congress lacks the ability to
encourage a State to regulate in a particular way, or that
Congress may not hold out incentives to the States as a
method of influencing a State's policy choices. Our cases
have identified a variety of methods, short of outright
coercion, by which Congress may urge a State to adopt a
legislative program consistent with federal interests. Two
of these methods are of particular relevance here.

First, under Congress' spending power, "Congress may
attach conditions on the receipt of federal funds." South
Dakota v. Dole, 483 U. S., at 206. Such conditions must
(among other requirements) bear some relationship to the
purpose of the federal spending, id., at 207-208, and n. 3;
otherwise, of course, the spending power could render
academic the Constitution's other grants and limits of
federal authority. Where the recipient of federal funds is a
State, as is not unusual today, the conditions attached to
the funds by Congress may influence a State's legislative
choices. See Kaden, Politics, Money, and State Sovereignty:
The Judicial Role, 79 Colum. L. Rev. 847, 874-881 (1979).
Dole was one such case: The Court found no constitutional
flaw in a federal statute directing the Secretary of Transportation to withhold federal highway funds from States
failing to adopt Congress' choice of a minimum drinking
age. Similar examples abound. See, e. g., Fullilove v.
Klutznick, 448 U.S. 448, 478-480 (1980); Massachusetts v.
United States, 435 U.S. 444, 461-462 (1978); Lau v.Nichols, 414 U.S. 563, 568-569 (1974); Oklahoma v. Civil
Service Comm'n, 330 U.S. 127, 142-144 (1947).

Second, where Congress has the authority to regulate
private activity under the Commerce Clause, we have
recognized Congress' power to offer States the choice of
regulating that activity according to federal standards or
having state law pre-empted by federal regulation. Hodel
v. Virginia Surface Mining & Reclamation Assn., Inc.,
supra, at 288. See also FERC v. Mississippi, supra, at
764-765. This arrangement, which has been termed "a
program of cooperative federalism," Hodel, supra, at 289, is
replicated in numerous federal statutory schemes. These
include the Clean Water Act, 86 Stat. 816, as amended, 33 U.S.C. § 1251et seq., see Arkansas v. Oklahoma, 503 U. S.
___, ___ (1992) (slip op., at 8) (Clean Water Act Act "anticipates a partnership between the States and the Federal
Government, animated by a shared objective"); the Occupational Safety and Health Act of 1970, 84 Stat. 1590, 29 U.S.C. § 651et seq., see Gade v. National Solid Wastes
Management Assn., ___ U. S. ___, ___ (1992) (slip op., at
___); the Resource Conservation and Recovery Act of 1976,
90 Stat. 2796, as amended, 42 U.S.C. § 6901et seq., see
United States Dept. of Energy v. Ohio, 503 U. S. ___, ___
(1992) (slip op., at 2); and the Alaska National Interest
Lands Conservation Act, 94 Stat. 2374, 16 U.S.C. § 3101et seq., see Kenaitze Indian Tribe v. Alaska, 860 F. 2d 312,
314 (CA9 1988), cert. denied, 491 U.S. 905 (1989).

By either of these two methods, as by any other permissible method of encouraging a State to conform to federal
policy choices, the residents of the State retain the ultimate
decision as to whether or not the State will comply. If a
State's citizens view federal policy as sufficiently contrary
to local interests, they may elect to decline a federal grant.
If state residents would prefer their government to devote
its attention and resources to problems other than those
deemed important by Congress, they may choose to have
the Federal Government rather than the State bear theexpense of a federally mandated regulatory program, and
they may continue to supplement that program to the
extent state law is not preempted. Where Congress
encourages state regulation rather than compelling it, state
governments remain responsive to the local electorate's
preferences; state officials remain accountable to the people.

By contrast, where the Federal Government compels
States to regulate, the accountability of both state and
federal officials is diminished. If the citizens of New York,
for example, do not consider that making provision for the
disposal of radioactive waste is in their best interest, they
may elect state officials who share their view. That view
can always be preempted under the Supremacy Clause if is
contrary to the national view, but in such a case it is the
Federal Government that makes the decision in full view of
the public, and it will be federal officials that suffer the
consequences if the decision turns out to be detrimental or
unpopular. But where the Federal Government directs the
States to regulate, it may be state officials who will bear
the brunt of public disapproval, while the federal officials
who devised the regulatory program may remain insulated
from the electoral ramifications of their decision. Accountability is thus diminished when, due to federal coercion,
elected state officials cannot regulate in accordance with the
views of the local electorate in matters not pre-empted by
federal regulation. See Merritt, 88 Colum. L. Rev., at
61-62; La Pierre, Political Accountability in the National
Political Process--The Alternative to Judicial Review of
Federalism Issues, 80 Nw. U. L. Rev. 577, 639-665 (1985).

With these principles in mind, we turn to the three
challenged provisions of the Low Level Radioactive Waste
Policy Amendments Act of 1985.

The parties in this case advance two quite different views
of the Act. As petitioners see it, the Act imposes a requirement directly upon the States that they regulate in the fieldof radioactive waste disposal in order to meet Congress'
mandate that "[e]ach State shall be responsible for providing . . . for the disposal of . . . low level radioactive waste."
42 U.S.C. § 2021c(a)(1)(A). Petitioners understand this
provision as a direct command from Congress, enforceable
independent of the three sets of incentives provided by the
Act. Respondents, on the other hand, read this provision
together with the incentives, and see the Act as affording
the States three sets of choices. According to respondents,
the Act permits a State to choose first between regulating
pursuant to federal standards and losing the right to a
share of the Secretary of Energy's escrow account; to choose
second between regulating pursuant to federal standards
and progressively losing access to disposal sites in other
States; and to choose third between regulating pursuant to
federal standards and taking title to the waste generated
within the State. Respondents thus interpret § 2021c(a)(1)(A), despite the statute's use of the word "shall," to
provide no more than an option which a State may elect or
eschew.

The Act could plausibly be understood either as a
mandate to regulate or as a series of incentives. Under
petitioners' view, however, § 2021c(a)(1)(A) of the Act would
clearly "commandee[r] the legislative processes of the States
by directly compelling them to enact and enforce a federal
regulatory program." Hodel v. Virginia Surface Mining &
Reclamation Assn., Inc., 452 U. S., at 288. We must reject
this interpretation of the provision for two reasons. First,
such an outcome would, to say the least, "upset the usual
constitutional balance of federal and state powers." Gregory
v. Ashcroft, 501 U. S., at ___ (slip op., at 6). "[I]t is incumbent upon the federal courts to be certain of Congress'
intent before finding that federal law overrides this balance," ibid. (internal quotation marks omitted), but the
Act's amenability to an equally plausible alternative
construction prevents us from possessing such certainty.
Second, "where an otherwise acceptable construction of astatute would raise serious constitutional problems, the
Court will construe the statute to avoid such problems
unless such construction is plainly contrary to the intent of
Congress." Edward J. DeBartolo Corp. v. Florida Gulf
Coast Building & Construction Trades Council, 485 U.S. 568, 575 (1988). This rule of statutory construction pushes
us away from petitioners' understanding of § 2021c(a)(1)(A)
of the Act, under which it compels the States to regulate
according to Congress' instructions.

We therefore decline petitioners' invitation to construe
§ 2021c(a)(1)(A), alone and in isolation, as a command to the
States independent of the remainder of the Act. Construed
as a whole, the Act comprises three sets of "incentives" for
the States to provide for the disposal of low level radioactive waste generated within their borders. We consider
each in turn.

The first set of incentives works in three steps. First,
Congress has authorized States with disposal sites to
impose a surcharge on radioactive waste received from
other States. Second, the Secretary of Energy collects a
portion of this surcharge and places the money in an escrow
account. Third, States achieving a series of milestones
receive portions of this fund.

The first of these steps is an unexceptionable exercise of
Congress' power to authorize the States to burden interstate commerce. While the Commerce Clause has long been
understood to limit the States' ability to discriminate
against interstate commerce, see, e. g., Wyoming v. Oklahoma, 502 U. S. ___, ___ (1992) (slip op., at 15-16); Cooley v.
Board of Wardens of Port of Philadelphia, 12 How. 299
(1851), that limit may be lifted, as it has been here, by an
expression of the "unambiguous intent" of Congress.
Wyoming, supra, at ___ (slip op., at 19); Prudential Ins. Co.
v. Benjamin, 328 U.S. 408, 427-431 (1946). Whether or
not the States would be permitted to burden the interstatetransport of low level radioactive waste in the absence of
Congress' approval, the States can clearly do so with
Congress' approval, which is what the Act gives them.

The second step, the Secretary's collection of a percentage
of the surcharge, is no more than a federal tax on interstate
commerce, which petitioners do not claim to be an invalid
exercise of either Congress' commerce or taxing power. Cf.
United States v. Sanchez, 340 U.S. 42, 44-45 (1950);
Steward Machine Co. v. Davis, 301 U.S. 548, 581-583
(1937).

The third step is a conditional exercise of Congress'
authority under the Spending Clause: Congress has placed
conditions--the achievement of the milestones--on the
receipt of federal funds. Petitioners do not contend that
Congress has exceeded its authority in any of the four
respects our cases have identified. See generally South
Dakota v. Dole, 483 U. S., at 207-208. The expenditure is
for the general welfare, Helvering v. Davis, 301 U.S. 619,
640-641 (1937); the States are required to use the money
they receive for the purpose of assuring the safe disposal of
radioactive waste. 42 U.S.C. § 2021e(d)(2)(E). The
conditions imposed are unambiguous, Pennhurst State
School and Hospital v. Halderman, 451 U. S., at 17; the Act
informs the States exactly what they must do and by when
they must do it in order to obtain a share of the escrow
account. The conditions imposed are reasonably related to
the purpose of the expenditure, Massachusetts v. United
States, 435 U. S., at 461; both the conditions and the
payments embody Congress' efforts to address the pressing
problem of radioactive waste disposal. Finally, petitioners
do not claim that the conditions imposed by the Act violate
any independent constitutional prohibition. Lawrence
County v. Lead Deadwood School Dist., 469 U.S. 256,
269-270 (1985).

Petitioners contend nevertheless that the form of these
expenditures removes them from the scope of Congress'
spending power. Petitioners emphasize the Act's instruction to the Secretary of Energy to "deposit all funds received
in a special escrow account. The funds so deposited shall
not be the property of the United States." 42 U.S.C. § 2021e(d)(2)(A). Petitioners argue that because the money
collected and redisbursed to the States is kept in an account
separate from the general treasury, because the Secretary
holds the funds only as a trustee, and because the States
themselves are largely able to control whether they will pay
into the escrow account or receive a share, the Act "in no
manner calls for the spending of federal funds." Reply Brief
for Petitioner State of New York 6.

The Constitution's grant to Congress of the authority to "pay the Debts and provide for the . . . general Welfare" has
never, however, been thought to mandate a particular form
of accounting. A great deal of federal spending comes from
segregated trust funds collected and spent for a particular
purpose. See, e. g., 23 U.S.C. § 118 (Highway Trust Fund);
42 U.S.C. § 401(a) (Federal Old Age and Survivors Insurance Trust Fund); 42 U.S.C. § 401(b) (Federal Disability
Insurance Trust Fund); 42 U.S.C. § 1395t (Federal Supplementary Medical Insurance Trust Fund). The Spending
Clause has never been construed to deprive Congress of
the power to structure federal spending in this manner.
Petitioners' argument regarding the States' ability to
determine the escrow account's income and disbursements
ignores the fact that Congress specifically provided the
States with this ability as a method of encouraging the
States to regulate according to the federal plan. That the
States are able to choose whether they will receive federal
funds does not make the resulting expenditures any less
federal; indeed, the location of such choice in the States is
an inherent element in any conditional exercise of Congress'
spending power.

The Act's first set of incentives, in which Congress has
conditioned grants to the States upon the States' attainment of a series of milestones, is thus well within the
authority of Congress under the Commerce and SpendingClauses. Because the first set of incentives is supported by
affirmative constitutional grants of power to Congress, it is
not inconsistent with the Tenth Amendment.

In the second set of incentives, Congress has authorized
States and regional compacts with disposal sites gradually
to increase the cost of access to the sites, and then to deny
access altogether, to radioactive waste generated in States
that do not meet federal deadlines. As a simple regulation,
this provision would be within the power of Congress to
authorize the States to discriminate against interstate
commerce. See Northeast Bancorp, Inc. v. Board of Governors, Fed. Reserve System, 472 U.S. 159, 174-175 (1985).
Where federal regulation of private activity is within the
scope of the Commerce Clause, we have recognized the
ability of Congress to offer states the choice of regulating
that activity according to federal standards or having state
law pre-empted by federal regulation. See Hodel v. Virginia
Surface Mining & Reclamation Association, 452 U. S., at
288; FERC v. Mississippi, 456 U. S., at 764-765.

This is the choice presented to nonsited States by the
Act's second set of incentives: States may either regulate
the disposal of radioactive waste according to federal
standards by attaining local or regional self sufficiency, or
their residents who produce radioactive waste will be
subject to federal regulation authorizing sited States and
regions to deny access to their disposal sites. The affected
States are not compelled by Congress to regulate, because
any burden caused by a State's refusal to regulate will fall
on those who generate waste and find no outlet for its
disposal, rather than on the State as a sovereign. A State
whose citizens do not wish it to attain the Act's milestones
may devote its attention and its resources to issues its
citizens deem more worthy; the choice remains at all times
with the residents of the State, not with Congress. The
State need not expend any funds, or participate in anyfederal program, if local residents do not view such expenditures or participation as worthwhile. Cf. Hodel, supra, at
288. Nor must the State abandon the field if it does not
accede to federal direction; the State may continue to
regulate the generation and disposal of radioactive waste in
any manner its citizens see fit.

The Act's second set of incentives thus represents a
conditional exercise of Congress' commerce power, along the
lines of those we have held to be within Congress' authority. As a result, the second set of incentives does not
intrude on the sovereignty reserved to the States by the
Tenth Amendment.

The take title provision is of a different character. This
third so called "incentive" offers States, as an alternative to
regulating pursuant to Congress' direction, the option of
taking title to and possession of the low level radioactive
waste generated within their borders and becoming liable
for all damages waste generators suffer as a result of the
States' failure to do so promptly. In this provision, Congress has crossed the line distinguishing encouragement
from coercion.

We must initially reject respondents' suggestion that,
because the take title provision will not take effect until
January 1, 1996, petitioners' challenge thereto is unripe. It
takes many years to develop a new disposal site. All
parties agree that New York must take action now in order
to avoid the take title provision's consequences, and no
party suggests that the State's waste generators will have
ceased producing waste by 1996. The issue is thus ripe for
review. Cf. Pacific Gas & Elec. Co. v. State Energy Resources Conservation and Development Comm'n, 461 U.S. 190,
201 (1983); Regional Rail Reorganization Act Cases, 419 U.S. 102, 144-145 (1974).

The take title provision offers state governments a "choice" of either accepting ownership of waste or regulatingaccording to the instructions of Congress. Respondents do
not claim that the Constitution would authorize Congress
to impose either option as a freestanding requirement. On
one hand, the Constitution would not permit Congress
simply to transfer radioactive waste from generators to
state governments. Such a forced transfer, standing alone,
would in principle be no different than a congressionally
compelled subsidy from state governments to radioactive
waste producers. The same is true of the provision requiring the States to become liable for the generators' damages.
Standing alone, this provision would be indistinguishable
from an Act of Congress directing the States to assume the
liabilities of certain state residents. Either type of federal
action would "commandeer" state governments into the
service of federal regulatory purposes, and would for this
reason be inconsistent with the Constitution's division of
authority between federal and state governments. On the
other hand, the second alternative held out to state governments--regulating pursuant to Congress' direction--would,
standing alone, present a simple command to state governments to implement legislation enacted by Congress. As we
have seen, the Constitution does not empower Congress to
subject state governments to this type of instruction.

Because an instruction to state governments to take title
to waste, standing alone, would be beyond the authority of
Congress, and because a direct order to regulate, standing
alone, would also be beyond the authority of Congress, it
follows that Congress lacks the power to offer the States a
choice between the two. Unlike the first two sets of
incentives, the take title incentive does not represent the
conditional exercise of any congressional power enumerated
in the Constitution. In this provision, Congress has not
held out the threat of exercising its spending power or its
commerce power; it has instead held out the threat, should
the States not regulate according to one federal instruction,
of simply forcing the States to submit to another federal
instruction. A choice between two unconstitutionallycoercive regulatory techniques is no choice at all. Either
way, "the Act commandeers the legislative processes of the
States by directly compelling them to enact and enforce a
federal regulatory program," Hodel v. Virginia Surface
Mining & Reclamation Assn., Inc., supra, at 288, an
outcome that has never been understood to lie within the
authority conferred upon Congress by the Constitution.

Respondents emphasize the latitude given to the States
to implement Congress' plan. The Act enables the States to
regulate pursuant to Congress' instructions in any number
of different ways. States may avoid taking title by contracting with sited regional compacts, by building a disposal site
alone or as part of a compact, or by permitting private
parties to build a disposal site. States that host sites may
employ a wide range of designs and disposal methods,
subject only to broad federal regulatory limits. This line of
reasoning, however, only underscores the critical alternative
a State lacks: A State may not decline to administer the
federal program. No matter which path the State chooses,
it must follow the direction of Congress.

The take title provision appears to be unique. No other
federal statute has been cited which offers a state government no option other than that of implementing legislation
enacted by Congress. Whether one views the take title
provision as lying outside Congress' enumerated powers, or
as infringing upon the core of state sovereignty reserved by
the Tenth Amendment, the provision is inconsistent with
the federal structure of our Government established by the
Constitution.

Respondents raise a number of objections to this understanding of the limits of Congress' power.

The United States proposes three alternative views of the
constitutional line separating state and federal authority. While each view concedes that Congress generally may not
compel state governments to regulate pursuant to federal
direction, each purports to find a limited domain in which
such coercion is permitted by the Constitution.

First, the United States argues that the Constitution's
prohibition of congressional directives to state governments
can be overcome where the federal interest is sufficiently
important to justify state submission. This argument
contains a kernel of truth: In determining whether the
Tenth Amendment limits the ability of Congress to subject
state governments to generally applicable laws, the Court
has in some cases stated that it will evaluate the strength
of federal interests in light of the degree to which such laws
would prevent the State from functioning as a sovereign;
that is, the extent to which such generally applicable laws
would impede a state government's responsibility to
represent and be accountable to the citizens of the State.
See, e. g., EEOC v. Wyoming, 460 U. S., at 242, n. 17;
Transportation Union v. Long Island R. Co., 455 U. S., at
684, n. 9; National League of Cities v. Usery, 426 U. S., at
853. The Court has more recently departed from this
approach. See, e. g., South Carolina v. Baker, 485 U. S., at
512-513; Garcia v. San Antonio Metropolitan Transit
Authority, 469 U. S., at 556-557. But whether or not a
particularly strong federal interest enables Congress to
bring state governments within the orbit of generally
applicable federal regulation, no Member of the Court has
ever suggested that such a federal interest would enable
Congress to command a state government to enact state
regulation. No matter how powerful the federal interest
involved, the Constitution simply does not give Congress
the authority to require the States to regulate. The
Constitution instead gives Congress the authority to
regulate matters directly and to pre-empt contrary state
regulation. Where a federal interest is sufficiently strong
to cause Congress to legislate, it must do so directly; it may
not conscript state governments as its agents.

Second, the United States argues that the Constitution
does, in some circumstances, permit federal directives to
state governments. Various cases are cited for this proposition, but none support it. Some of these cases discuss the
well established power of Congress to pass laws enforceable
in state courts. See Testa v. Katt, 330 U.S. 386 (1947);
Palmore v. United States, 411 U.S. 389, 402 (1973); see
also Mondou v. New York, N. H. & H. R. Co., 223 U.S. 1,
57 (1912); Claflin v. Houseman, 93 U.S. 130, 136-137
(1876). These cases involve no more than an application of
the Supremacy Clause's provision that federal law "shall be
the supreme Law of the Land," enforceable in every State.
More to the point, all involve congressional regulation of
individuals, not congressional requirements that States
regulate. Federal statutes enforceable in state courts do, in
a sense, direct state judges to enforce them, but this sort of
federal "direction" of state judges is mandated by the text
of the Supremacy Clause. No comparable constitutional
provision authorizes Congress to command state legislatures to legislate.

Additional cases cited by the United States discuss the
power of federal courts to order state officials to comply
with federal law. See Puerto Rico v. Branstad, 483 U.S. 219, 228 (1987); Washington v. Washington State Commercial Passenger Fishing Vessel Assn., 443 U.S. 658, 695
(1979); Illinois v. City of Milwaukee, 406 U.S. 91, 106-108
(1972); see also Cooper v. Aaron, 358 U.S. 1, 18-19 (1958);
Brown v. Board of Ed., 349 U.S. 294, 300 (1955); Ex parte
Young, 209 U.S. 123, 155-156 (1908). Again, however, the
text of the Constitution plainly confers this authority on the
federal courts, the "judicial Power" of which "shall extend
to all Cases, in Law and Equity, arising under this Constitution, [and] the Laws of the United States . . . ; [and] to
Controversies between two or more States; [and] between
a State and Citizens of another State." U. S. Const., Art.
III, § 2. The Constitution contains no analogous grant of
authority to Congress. Moreover, the Supremacy Clausemakes federal law paramount over the contrary positions of
state officials; the power of federal courts to enforce federal
law thus presupposes some authority to order state officials
to comply. See Puerto Rico v. Branstad, supra, at 227-228
(overruling Kentucky v. Dennison, 24 How. 66 (1861)).

In sum, the cases relied upon by the United States hold
only that federal law is enforceable in state courts and that
federal courts may in proper circumstances order state
officials to comply with federal law, propositions that by no
means imply any authority on the part of Congress to
mandate state regulation.

Third, the United States, supported by the three sited
regional compacts as amici, argues that the Constitution
envisions a role for Congress as an arbiter of interstate
disputes. The United States observes that federal courts,
and this Court in particular, have frequently resolved
conflicts among States. See, e. g., Arkansas v. Oklahoma,
503 U. S. ___ (1992); Wyoming v. Oklahoma, 502 U. S. ___
(1992). Many of these disputes have involved the allocation
of shared resources among the States, a category perhaps
broad enough to encompass the allocation of scarce disposal
space for radioactive waste. See, e. g., Colorado v. New
Mexico, 459 U.S. 176 (1982); Arizona v. California, 373 U.S. 546 (1963). The United States suggests that if the
Court may resolve such interstate disputes, Congress can
surely do the same under the Commerce Clause. The
regional compacts support this argument with a series of
quotations from The Federalist and other contemporaneous
documents, which the compacts contend demonstrate that
the Framers established a strong national legislature for
the purpose of resolving trade disputes among the States.
Brief for Rocky Mountain Low Level Radioactive Waste
Compact et al. as Amici Curiae 17, and n. 16.

While the Framers no doubt endowed Congress with the
power to regulate interstate commerce in order to avoid
further instances of the interstate trade disputes that were
common under the Articles of Confederation, the Framersdid not intend that Congress should exercise that power
through the mechanism of mandating state regulation. The
Constitution established Congress as "a superintending
authority over the reciprocal trade" among the States, The
Federalist No. 42, p. 268 (C. Rossiter ed. 1961), by empowering Congress to regulate that trade directly, not by
authorizing Congress to issue trade related orders to state
governments. As Madison and Hamilton explained, "a
sovereignty over sovereigns, a government over governments, a legislation for communities, as contradistinguished
from individuals, as it is a solecism in theory, so in practice
it is subversive of the order and ends of civil polity." Id.,
No. 20, p. 138.

The sited State respondents focus their attention on the
process by which the Act was formulated. They correctly
observe that public officials representing the State of New
York lent their support to the Act's enactment. A Deputy
Commissioner of the State's Energy Office testified in favor
of the Act. See Low Level Waste Legislation: Hearings on
H.R. 862, H.R. 1046, H.R. 1083, and H.R. 1267 before the
Subcommittee on Energy and the Environment of the
House Comm. on Interior and Insular Affairs, 99th Cong.,
1st Sess. 97-98, 190-199 (1985) (testimony of Charles
Guinn). Senator Moynihan of New York spoke in support
of the Act on the floor of the Senate. 131 Cong. Rec. 38423
(1985). Respondents note that the Act embodies a bargain
among the sited and unsited States, a compromise to which
New York was a willing participant and from which New
York has reaped much benefit. Respondents then pose
what appears at first to be a troubling question: How can
a federal statute be found an unconstitutional infringement
of State sovereignty when state officials consented to the
statute's enactment?

The answer follows from an understanding of the fundamental purpose served by our Government's federal structure. The Constitution does not protect the sovereignty of
States for the benefit of the States or state governments as
abstract political entities, or even for the benefit of the
public officials governing the States. To the contrary, the
Constitution divides authority between federal and state
governments for the protection of individuals. State
sovereignty is not just an end in itself: "Rather, federalism
secures to citizens the liberties that derive from the
diffusion of sovereign power." Coleman v. Thompson, 501
U. S. ___, ___ (1991) (slip op., at 2) (Blackmun, J., dissenting). "Just as the separation and independence of the
coordinate Branches of the Federal Government serves to
prevent the accumulation of excessive power in any one
Branch, a healthy balance of power between the States and
the Federal Government will reduce the risk of tyranny and
abuse from either front." Gregory v. Ashcroft, 501 U. S., at
___ (1991) (slip op., at 4). See The Federalist No. 51,
p. 323.

Where Congress exceeds its authority relative to the
States, therefore, the departure from the constitutional plan
cannot be ratified by the "consent" of state officials. An
analogy to the separation of powers among the Branches of
the Federal Government clarifies this point. The Constitution's division of power among the three Branches is
violated where one Branch invades the territory of another,
whether or not the encroached upon Branch approves the
encroachment. In Buckley v. Valeo, 424 U.S. 1, 118-137
(1976), for instance, the Court held that the Congress had
infringed the President's appointment power, despite the
fact that the President himself had manifested his consent
to the statute that caused the infringement by signing it
into law. See National League of Cities v. Usery, 426 U. S.,
at 842, n. 12. In INS v. Chadha, 462 U.S. 919, 944-959
(1983), we held that the legislative veto violated the
constitutional requirement that legislation be presented to
the President, despite Presidents' approval of hundreds of
statutes containing a legislative veto provision. See id., at944-945. The constitutional authority of Congress cannot
be expanded by the "consent" of the governmental unit
whose domain is thereby narrowed, whether that unit is the
Executive Branch or the States.

State officials thus cannot consent to the enlargement of
the powers of Congress beyond those enumerated in the
Constitution. Indeed, the facts of this case raise the
possibility that powerful incentives might lead both federal
and state officials to view departures from the federal
structure to be in their personal interests. Most citizens
recognize the need for radioactive waste disposal sites, but
few want sites near their homes. As a result, while it
would be well within the authority of either federal or state
officials to choose where the disposal sites will be, it is
likely to be in the political interest of each individual
official to avoid being held accountable to the voters for the
choice of location. If a federal official is faced with the
alternatives of choosing a location or directing the States to
do it, the official may well prefer the latter, as a means of
shifting responsibility for the eventual decision. If a state
official is faced with the same set of alternatives--choosing
a location or having Congress direct the choice of a location--the state official may also prefer the latter, as it may
permit the avoidance of personal responsibility. The
interests of public officials thus may not coincide with the
Constitution's intergovernmental allocation of authority.
Where state officials purport to submit to the direction of
Congress in this manner, federalism is hardly being
advanced.

Nor does the State's prior support for the Act estop it
from asserting the Act's unconstitutionality. While New
York has received the benefit of the Act in the form of a few
more years of access to disposal sites in other States, New
York has never joined a regional radioactive waste compact.
Any estoppel implications that might flow from membership
in a compact, see West Virginia ex rel. Dyer v. Sims, 341 U.S. 22, 35-36 (1951) (Jackson, J., concurring), thus do notconcern us here. The fact that the Act, like much federal
legislation, embodies a compromise among the States does
not elevate the Act (or the antecedent discussions among
representatives of the States) to the status of an interstate
agreement requiring Congress' approval under the Compact
Clause. Cf. Holmes v. Jennison, 14 Pet. 540, 572 (1840)
(plurality opinion). That a party collaborated with others
in seeking legislation has never been understood to estop
the party from challenging that legislation in subsequent
litigation.

Petitioners also contend that the Act is inconsistent with
the Constitution's Guarantee Clause, which directs the
United States to "guarantee to every State in this Union a
Republican Form of Government." U. S. Const., Art. IV, § 4.
Because we have found the take title provision of the Act
irreconcilable with the powers delegated to Congress by the
Constitution and hence with the Tenth Amendment's
reservation to the States of those powers not delegated to
the Federal Government, we need only address the applicability of the Guarantee Clause to the Act's other two
challenged provisions.

We approach the issue with some trepidation, because the
Guarantee Clause has been an infrequent basis for litigation throughout our history. In most of the cases in which
the Court has been asked to apply the Clause, the Court
has found the claims presented to be nonjusticiable under
the "political question" doctrine. See, e. g., City of Rome v.
United States, 446 U.S. 156, 182, n. 17 (1980) (challenge to
the preclearance requirements of the Voting Rights Act);
Baker v. Carr, 369 U.S. 186, 218-229 (1962) (challenge to
apportionment of state legislative districts); Pacific States
Tel. & Tel. Co. v. Oregon, 223 U.S. 118, 140-151 (1912)
(challenge to initiative and referendum provisions of state
constitution).

The view that the Guarantee Clause implicates only
nonjusticiable political questions has its origin in Luther v.
Borden, 7 How. 1 (1849), in which the Court was asked to
decide, in the wake of Dorr's Rebellion, which of two rival
governments was the legitimate government of Rhode
Island. The Court held that "it rests with Congress," not
the judiciary, "to decide what government is the established
one in a State." Id., at 42. Over the following century, this
limited holding metamorphosed into the sweeping assertion
that "[v]iolation of the great guaranty of a republican form
of government in States cannot be challenged in the courts."
Colegrove v. Green, 328 U.S. 549, 556 (1946) (plurality
opinion).

This view has not always been accepted. In a group of
cases decided before the holding of Luther was elevated into
a general rule of nonjusticiability, the Court addressed the
merits of claims founded on the Guarantee Clause without
any suggestion that the claims were not justiciable. See
Kies v. Lowrey, 199 U.S. 233, 239 (1905); Forsyth v. Hammond, 166 U.S. 506, 519 (1897); In re Duncan, 139 U.S. 449, 461-462 (1891); Minor v. Happersett, 21 Wall. 162,
175-176 (1875). See also Plessy v. Ferguson, 163 U.S. 537,
563-564 (1896) (Harlan, J., dissenting) (racial segregation "inconsistent with the guarantee given by the Constitution
to each State of a republican form of government").

We need not resolve this difficult question today. Even
if we assume that petitioners' claim is justiciable, neither
the monetary incentives provided by the Act nor the
possibility that a State's waste producers may find themselves excluded from the disposal sites of another State can
reasonably be said to deny any State a republican form of
government. As we have seen, these two incentives
represent permissible conditional exercises of Congress'
authority under the Spending and Commerce Clauses
respectively, in forms that have now grown commonplace.
Under each, Congress offers the States a legitimate choice
rather than issuing an unavoidable command. The States
thereby retain the ability to set their legislative agendas;
state government officials remain accountable to the local
electorate. The twin threats imposed by the first two
challenged provisions of the Act--that New York may miss
out on a share of federal spending or that those generating
radioactive waste within New York may lose out of state
disposal outlets--do not pose any realistic risk of altering
the form or the method of functioning of New York's
government. Thus even indulging the assumption that the
Guarantee Clause provides a basis upon which a State or
its subdivisions may sue to enjoin the enforcement of a
federal statute, petitioners have not made out such a claim
in this case.

Having determined that the take title provision exceeds
the powers of Congress, we must consider whether it is
severable from the rest of the Act.

"The standard for determining the severability of an
unconstitutional provision is well established: Unless it is
evident that the Legislature would not have enacted those
provisions which are within its power, independently of that
which is not, the invalid part may be dropped if what is leftis fully operative as a law." Alaska Airlines, Inc. v. Brock,
480 U.S. 678, 684 (1987) (internal quotation marks
omitted). While the Act itself contains no statement of
whether its provisions are severable, "[i]n the absence of a
severability clause, . . . Congress' silence is just
that--silence--and does not raise a presumption against
severability." Id., at 686. Common sense suggests that
where Congress has enacted a statutory scheme for an
obvious purpose, and where Congress has included a series
of provisions operating as incentives to achieve that
purpose, the invalidation of one of the incentives should not
ordinarily cause Congress' overall intent to be frustrated.
As the Court has observed, "it is not to be presumed that
the legislature was legislating for the mere sake of imposing penalties, but the penalties . . . were simply in aid of
the main purpose of the statute. They may fail, and still
the great body of the statute have operative force, and the
force contemplated by the legislature in its enactment."
Reagan v. Farmers' Loan & Trust Co., 154 U.S. 362, 396
(1894). See also United States v. Jackson, 390 U.S. 570,
585-586 (1968).

It is apparent in light of these principles that the take
title provision may be severed without doing violence to the
rest of the Act. The Act is still operative and it still serves
Congress' objective of encouraging the States to attain local
or regional self sufficiency in the disposal of low level
radioactive waste. It still includes two incentives that coax
the States along this road. A State whose radioactive waste
generators are unable to gain access to disposal sites in
other States may encounter considerable internal pressure
to provide for the disposal of waste, even without the
prospect of taking title. The sited regional compacts need
not accept New York's waste after the seven year transition
period expires, so any burden caused by New York's failure
to secure a disposal site will not be borne by the residents
of other States. The purpose of the Act is not defeated by

the invalidation of the take title provision, so we may leave
the remainder of the Act in force.

Some truths are so basic that, like the air around us, they
are easily overlooked. Much of the Constitution is concerned with setting forth the form of our government, and
the courts have traditionally invalidated measures deviating from that form. The result may appear "formalistic" in
a given case to partisans of the measure at issue, because
such measures are typically the product of the era's
perceived necessity. But the Constitution protects us from
our own best intentions: It divides power among sovereigns
and among branches of government precisely so that we
may resist the temptation to concentrate power in one
location as an expedient solution to the crisis of the day.
The shortage of disposal sites for radioactive waste is a
pressing national problem, but a judiciary that licensed
extra constitutional government with each issue of comparable gravity would, in the long run, be far worse.

States are not mere political subdivisions of the United
States. State governments are neither regional offices nor
administrative agencies of the Federal Government. The
positions occupied by state officials appear nowhere on the
Federal Government's most detailed organizational chart.
The Constitution instead "leaves to the several States a
residuary and inviolable sovereignty," The Federalist No.
39, p. 245 (C. Rossiter ed. 1961), reserved explicitly to the
States by the Tenth Amendment.

Whatever the outer limits of that sovereignty may be, one
thing is clear: The Federal Government may not compel the
States to enact or administer a federal regulatory program.
The Constitution permits both the Federal Government and
the States to enact legislation regarding the disposal of low
level radioactive waste. The Constitution enables the
Federal Government to pre-empt state regulation contrary
to federal interests, and it permits the Federal Governmentto hold out incentives to the States as a means of encouraging them to adopt suggested regulatory schemes. It does
not, however, authorize Congress simply to direct the States
to provide for the disposal of the radioactive waste generated within their borders. While there may be many constitutional methods of achieving regional self sufficiency in
radioactive waste disposal, the method Congress has chosen
is not one of them. The judgment of the Court of Appeals
is accordingly